This invention relates to a low noise level internal combustion engine, and more particularly to a bearing support beam structure securely connected to a cylinder block to rotatably support a crankshaft and improve the flexural rigidity of the cylinder block.
In connection with an internal combustion engine for use with an automotive vehicle, it has been proposed to employ a bearing support beam structure to be securely connected to the lower section of a cylinder block in a manner to rotatably support a crankshaft, in which main bearings are carried on the incorporated bearing support beam structure and cylinder block. By virtue of the bearing support beam structure, the flexural rigidity of the cylinder block can be increased, thereby decreasing engine noise emitted outside.